This proposal is designed to investigate the mechanism of defective monocyte chemotaxis in patient with the cutaneous lymphoma, mycosis fungoides. Both in vitro techniques using column purified sub populations of lymphocytes and monocytes to characterize their interaction and in vivo techniques using microchemotaxis skin chambers will be utilized. Detailed in vitro investigation into the nature of the lymphocyte "helper" effect in monocyte chemotaxis that is deleted in mycosis fungoides will be studied.